/*
Given a binary tree, return the inorder traversal of its nodes' values.

For example:
Given binary tree {1,#,2,3},
   1
    \
     2
    /
   3
return [1,3,2].

Note: Recursive solution is trivial, could you do it iteratively?
*/

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<int> inorderTraversal(TreeNode *root) {
        vector<int> results;
        if (!root) return results;
        TreeNode *cur = root;
        stack<TreeNode *> s;
        do {
            if (cur) {
                s.push(cur);
                cur = cur->left;
            } else {
                cur = s.top();
                s.pop();
                results.push_back(cur->val);
                cur = (cur->right)?(cur->right):NULL;
            }
        } while(!s.empty() || cur);
        return results;
    }
};
